Automatic choke valve



NOV. 16, I E PERR|N 4 AUTOMATIC CHOKE VALVE origial Filed March y11; 1935` AZhwentor: 1359.2 ma www M7 Gttornegs Patented Nov. 1 6, 1943 n -TOMA'r-ic Gironi; vLv

Lester'E. PerrijneyDetroit, Mich., assgnorto Gen? eral Motors Corporation, Detroit, Mcha-afcory poration of Delaware original applicatonfmarcfi, 1935,'sria1 Nq.)

10,512. Dividedjand this application'December A y30; 19510,`Seral No. 372,315 k v 13 claims.-1 miles-,119) i This invention has todo with mechanisms for automatically operating the chokevalves ofjcarburetors of internal combustionV engines, and has for its principal object to provide a mechanism, which will without attention on the part of the operator of theengineyadjustthe choke valve of thecarburetor to the various-positionsinT which ita-'should be while ther engine 'is being.

started and operatedv under various onditionhsff` L t The invention with which4 this a'p'plic'zationg which is a division of Amy Patent No. 2,226,580, December 31, 1940,A is concerned, resides inan automatic choke valvel .operatingl mechanism which includes engine intake manifoldsuction and temperature actuatedzelements, `and whose principal features are extreme simplicity` in construction` and installationfandfa jsnap? type` thermostat. l

For arbetter understanding'of the nature and objects of this invention reference is madej to the following specification, in which is described the preferred embodimentof theinventionwhichis illustrated inthe accompanying, drawingj Inl the accompanying drawing: l f ligure 1 is a View of automatic choke -valve op erating mechanism".in accordance :Withf'm'y i nvention installed on an internal kcomblilsntion enf.-Y

gme, .7 t

Figure 2 is an enlarged sectional yiewor the automaticy choke valve operating `Vmechanism 'shown in Figurel; Y A Y e t In 'thef drawing, the reference characterF I3y indicates the intakemanifoldfof Yan internal combustion engine, ,and the reference character I a carburetor which is mounted `onthe intake. manifold. t, Y, Through thefbody of .thecarburetor I0 extends a duct II, throughwhose upper lend` air enters thecarburetonand from Vvvhoserlower end acombustible mixture vofiuel and air isdis-'f charged into the intake manifold I3.V .Therpor-f tion of the intake manifold 'into'which theyco'mbustible mixture venters from the carburetor, isl surrounded'by a jacket I2, through which" ex'- haust gases from theengine may be circulated to heat-the'c'ombusnble mixture. l 1

In the lower end of the duct Il, there` is located a throttle valve I5 of the butterfly type; by which the rate atnwhichv the `carburetor VIll supplies Combustible .mixture ,to the cylinders, and thus the speed loi thefengilne is regulated.. The throttle valve `I5 is mounted o n aishaft Ill," which is journaled in thebodyof the carburetor. 'Il'ov the .shaft I4 is iixdjan" operatingl lever-02, which Visarranged torbe' actuated by the oprator ofthe `engine thrdu'ghal link 6I,"v al lever 60 and asha'ftZLjV f ,1

, In the upper end of theduct I I'there is located a choke valve I1 ofthe butterfly ,type, by which the entrance' of air into the carburetor, and thus thej richness. ,of p the combustible 'mixture which thelcarburetor lsupplies to the cylinders oi thev ,engineis regulated. The choke valve is mllhled lona.` shaft I6, whichiisjournaled in the body lofthe carburetor andlis vunbalanced',so Vthat flow' of air into the carburetor tends toopen it.` To control the` chokefvalvejsl1,"there' is `provided mechanism which is carried `by a plate 05, which is Ymounted over and closes an opening 0l in the upper'w'all of theintake manifold I3, near the jacket |2.i On' the undersurface'of the plateBS Fthere lare formedtwo bosses 9'1 and 98, which projectinto ,the intake manifold '|3, and are spacedlengthwise Ltlfiereof.'`I` In a slot 99,in the boss z'.-l'|, there is jseated one Aend of a strip |00.Y The' other. end of the stripV lqextends into a bore` |0| in the boss 9 8,and abuts against a set screw |02, which is `threadedinto'the bore; e The strip |00 is a bimetal onel and conseduently a thermostaha'ndjisV installed `in the s 1ot}r99 'and fbore IBI with the, layer `of metal withjthe higher temperature c oeilicientof` ex.

pan'sionv on the underside of the'layer vofzmetal with Lthe lowerteinperature coefficient ofJeX-' pansion," Thelset screw |02 is adjusted so as to make the distance between itsrinnerend andthe bottom4 ofthe "slot 99in the Vboss 91 lessktlian, theleng'th ofthe thermostat ,I00 by an amount sufficient to bow theY thermostat considerably Y, 'I'heA directionofubow vwillidepend on the temperature of the thermostat, downwardly Aifthe temperature is, aboveY aj preselected value,` and upwardly if the temperature is below thelpreselected value. Byfreason of the circumstance thatfthe distance between 'the' abutments of thev thermostat |00"`isA less than tl'ievlength of the thermostat, the' thermostat isa ,snap type' device, i. e., a device which moves instantaneously,V from or to aconsiderably'upwardly bowed tqjor from fa' considejrably downwardly bowed position upvorl,v a change in temperature, from below or above to :above orfbelow the prese-f. lected value, and does not occupy any,interme-fA diate position except instantaneously; Of course, when bowed eithe'upwardly orf, downwardly, fthe thermostat |00 can witlriin` limits iunction as a gradationall type device `and as a' spring. j N'Ifhrough the .plate 9 5..-mi dway between the bossesl and 98 extendsanjopeningIUS, which is 'sealed by, a `ilexible ,diaphragm v|04, whose the choke valve Il. Through the center of the flexible diaphragm |04 extends a pin whose lower end is suitably secured to the thermostat |00, and whose upper end isv piyotally connected by a pin ||2 to the lever |08 `between itsends. The hole in the diaphragm through which the pin extends is sealed, and the rod is secured to the diaphragm by discs 3 between which the thermostat farther downwardly, and thus the farther opening of the choke valve and the` consequent further leaning of the combustible mixture, which is desirable under these circumstances will be effected.

Regardless ofthe position'of thethermostat,

whenever the .engine is operating 'under its ownV power, changes in the rate of flow of air into the carburetor and'intake manifold suction acting on the choke Valve and the flexible diaphragm, respectively, will move the choke valve' somewhat against the resistance of the thermothe central portion of the diaphragm is clampedi n When an engine equipped with the choke valve operating mechanism shown in the drawing and hereinbefore described is not operating, the position of the choke valve will depend vupon the temperature of the engine. If thetemperature of the engine've'xceeds apreselected value, the thermostat |00 will be bowed downwardly to an extent Whichdepends upon how much the temperature exceeds the preselected/value, and will consequently hold the chokevalve open to the proper position, forl starting the engine at the prevailing temperature. If, however, the temperature of 'the engine is below the preseleoted value, .the thermostat will be bowed upwardly to an extent which depends upon how much the temperature is below the Vpreselected value and will,` consequently, hold 'the choke valve Vclosed to the proper position for starting the' engine' under the prevailing temperature. .y

` If the engine is started when its temperature is above the preselected value, the chokevalve will, when .the engine beginsto; operate normally under its o own power; be opened somewhat farther against the resistance of thel thermostat by the `flow of air into the; carburetor, and in-. take vmanifold.'suction acting on the'choke Valve, and the Vflexible diaphragm |04,V respectively, and effectV the ,leaning of the combustible'mixture` supplied by the carburetor 'to the engine, whichv is desirable atfthistime. As the engine warms up n heat derived from the Ycombustible mixture Ilowing past it,and heat conducted through the wall of the intake manifold I3 and the plate 95, will-raise the temperature of Athe thermostat, and, gradually bow it farther downwardly, land thus the farther opening of the choke Valve, and the.lcon',seq'uentlyr further leaning of lthe,` combustible mixture, which is desirable under these circumstances'will bee'ffected. v Y.

If'the engine is started when its temperature is below the preselected value, the choke valve will, 'when 'the engine begins to operate 'normally "under its own jpowe'r., be opened .somewhat against the 'resistance of the thermostat bythe ow of` air intoV the carburetonfand intake manifoldsuction actingon the choke valve and the flexible diaphragm, respectively,`and effectthe leaning of the combustiblemixture which is'desirab'le at this time., As the engine warms up heat derived Vfrom the combustible mixture flowing past it, and lheat conducted through the wall ofthe intake manifoldand thepl'ate 95, will raise the teimueratureA of 'the thermostat. Increase 'in :the 'temperature 'o f 'the thermostat' will graduailyoeerease its upward bow, until the temperature reaches the 'preselected value, then 'instantaneously reverse the :curvature or the thennosta't, and thereafter, Igradually-'bow stat, and eiect the leaning or enriching of the combustible mixture supplied by the'carburetor to the engine which is desirable when such changes occur.

` aprocess which will be clear from what has been buretor in whichv there isincorpor'ated a-lohokev valve, a member'inwhich thereis a passage which. connectsfthe carburetor Vwith'la cylinder of the said withregard to the operation of the mechanism,continuously maintain'the' choke valve at the proper'positiontfor starting the engine under the existing conditions.

l I claim;

1.`In an internal'combustion'engine a car.- b'uretor inwhich'there is incorporated achoke valve, 'aV member with a passage in itrwhich connects theearburetor withal cylinderof the 'en- Y gine'fjaniember'which 'constitutes'a closure for an opening fin the wall of the first specified member, a thermostat `mounted. on. the second speciedfmember within the mentioned passage'ja member which extends through anopening in the second speciedrmernber andconnects the thermostat Vwith :the choke valve, and ailexible member responsiverto pressure variations ,within ther mentioned passage which is secured to the third' specified member, and seals the opening in theV secondfspecied member .through Ewhich it extends.

2.V1InA anl internal,combustionA engine car-g` buretor, avalve disposed in theomain air admission orifice of the `Carlouretor to regulatefthe entrance `of air intofthecarburetor, and a thermo- 7 stat vvliichis'so constructed and arranged thatl it'moves the mentioned valve abruptly from one position to a substantially different position when the temperature reaches'a preselected value.` 1 'f 3i Inan internal'eombustion engine carburetor,

a valve disposed in the main air admission orifice of the carburetor to regulate th-efentrance of air into the'carburetor, and a bimetal thermostat ofA which aiportionisbowed Vand restrained fromA extension sov arranged and connected toy the mentioned valvethat it movesit abruptly fromv one position to a substantially diiferentposition when the temperature reaches a preselected value. .4; In aninternal combustion engine, 'a carengineand Y an orifice` which communicates-with the passage, a closure for the orice vwhich includes amember responsive to variations in pressure Within the mentionedpassage connected fto;

the choke valve, and a thermostat disposed within the passage andconnected to the second specified member,y

5. Infan internal combustion engine, a car-`v buretorv in Whichrthereflis incorporated a choke l Valve which isj'unbalariced'so that vflow, of air into the carburetorl tends to openft, a member responsivefto an' engine operating condition con-.. A nected to the choke valve so` that it tends to ,open4 it when the engine is operating, and athermo-vv stat connected to the specied member and therethrough to the choke valve so that it tends'to open and close the choke valve when the temperature of the engine rises and falls.

6. In an vinternal combustion engine,Y a carburetor in which there is incorporated a choke valve, a member with a'passage in it VWhich con- I pressure in the passage falls; and a thermostatv connected to the second `specified member and therethrough to the choke valve so that it tends to open and close the choke valve when the temperature of the engine rises and falls.

7. In an internal combustion engine, a carvalve, a member in which there isa passage which connects the carburetor with a cylinder of the engine, and an orifice which communicates with the passage, a closure for the` oricevwhich includes a member responsiveto variations in pressure Within the mentioned, passage connected to the .choke valve, and a thermostat so constructed and arranged that it moves abruptly from one position to a substantially different position, when the temperature reaches a preselected valuedisposed within the passage and connected tothe secondspecied member and there- Y buretor which includes a choke valve and athrottle valve, a member with a passage in it which connects the carburetor with a cylinder of the engine, and means for regulating the positionof the choke valve which includes a thermostat disposed within the mentioned passage on the engine side of the throttle valve and connected to the choke valve so that it may move it.

8. In an internal combustion engine, a carburetor which includes a choke valve and a throttle valve, a member with a passage in it ,which connects the .carburetor with a cylinder of the engine, means for heating combustible mixture passing through the mentioned passage from the carburetor to the engine, andmeans for regulatin-g the position ofthe choke valve, LWhich includes a thermostat disposed Within the mentioned passage on the engine side of the throttle valve Vand the first specified means sothat it is heated by the combustible mixture heated by the first specied means. j v

9. InV an internal combustion engine, a member including a carburetor, With a passage in it through which air travels from the atmosphere through to the choke valve. Y

11. In an internal combustion engine, a mem- Y ber including acarburetor, with a passage in it through which air travels from the atmosphere to a cylinder of the engine, a choke valve in the carburetor, and means, including a memberand a thermostat, for regulating the position of the choke valve, the member being responsive to variations in pressure Within the mentioned passage and the thermostat being so constructed and arranged that it moves abruptly Vfrom one position to a substantially different position when the temperature reaches al preselected value.

' 12, In an internal combustion engine, a member, including a carburetor, with av passage in it through which air travels from the atmosphere to a cylinder of the engine, a choke valve in the carburetor, and means for regulating the position of the choke valve which includes a thermostat so constructed and arranged, that it moves abruptly from one position to a substantially different position, when the temperature reaches a preselected value, disposed within the mentioned passage.

A 13, In an internal combustion engine, a member, including a carburetor, with a passage in it through which air travels from the atmosphere to a cylinder of the engine, a choke valve in the carburetor, and means for regulating the position of the choke valve which includes a member responsive to variations in pressure within the mentionedV passage, and a thermostat so constructed and arranged, that it moves abruptly from one position to a substantially diierent 1 position, when the temperature reaches a prev passage.

LESTER E. PERRINE. 

